Magnetic window cleaning apparatus

ABSTRACT

MASTER AND SLAVE UNITS ARE PROVIDED AND EACH UNIT HAS A ONE-PIECE, PLURAL-POLARIZED, PERMANENT MAGNET. THE MAGNET IS ILLUSTRATED WITH ITS POLES WITH TWO DIFFERENT SHAPESRECTANGULAR OR TRIANGULAR. A LAYER OF RESILIENT POLYURETHANE IS SECURED TO THE FACE OF EACH MAGNET AND A DISPOSABLE SHEET OF CLEANING MATERIAL OVERLIES THIS LAYER. A FERROMAGNETIC FASTNER LIES OUTWARDLY OF THE DISPOSABLE SHEET AND IS HELD BY THE MAGNET. THE FASTENER ALSO SERVES TO REDUCE FRICTION BETWEEN THE SHEET AND THE WINDOW.

Oct. 5, 197B .1.A. KAFTAN MAGNETIC WINDOW CLEANING APPARATUS 2 Sheets-Sheet l Filed March 17, 1969 wfyk @at *Mum W550/fafa J. A. KAFTAN MAGNETIC WINDOW CLEANING APPARATUS 2 Sheets-Sheet 2 Oct. 5, 1971 Filed March 17, 1969 IVI I a .2 M E .H

United States Patent O 3,609,793 MAGNETIC WINDOW CLEANING APPARATUS John A. Kaftan, 330 W. Railroad, Marengo, Ill. 60152 Filed Mar. 17, 1969, ser. No. 807,524 Int. Cl. A471 l 08 U.S. CI. -220 13 Claims ABSTRACT OF THE DISCLOSURE Master and slave units are provided and each unit has a one-piece, plural-polarized, permanent magnet. The magnet is illustrated with its poles with two different shapesrectangular or triangular. A layer of resilient polyurethane is secured to the face of each magnet and a disposable sheet of cleaning material overlies this layer. A ferro magnetic fastener lies outwardly of the disposable sheet and is held by the magnet. The fastener also serves to reduce friction between the sheet and the window.

BACKGROUND The invention pertains to window cleaners and more particularly to a window cleaner which utilizes magnetic attraction.

Apparatus of this general type is useful for cleaning hard-to-reach portions of a window and is particularly handy in cleaning the outside of a window from the inside. Various devices of this general type have been previously suggested. In general, the devices have included a pair of units positioned on opposite sides of a window, and having a magnetic member in each unit to provide a magnetic circuit to hold the units contiguous to the window. In theory, the master unit could be moved over the window and the slave unit would follow.

To be commercially practical, such apparatus must be simple and economical. It is desirable that the cleaning material be quickly and easily positioned and removed. This necessitates a simple, but effective fastener. Additionally, it is desirable that the apparatus have good tracking characteristics when moved in a circular pattern, since window cleaning is often done in such a pattern.

SUMMARY The present invention relates generally to cleaning apparatus, and more particularly to a magnetic window cleaning apparatus.

It is an object of the present invention to provide a magnetic window cleaning apparatus in which the cleaning material is easily replaced.

Another object is to provide a magnetic window cleaning apparatus which utilizes magnetism to hold the cleaning material in position.

Still another object is to provide a magnetic window cleaning apparatus which includes means for reducing the friction between the cleaning material and the Window.

Yet another object is to provide a magnetic window cleaning apparatus including master and slave units and having means for limiting the distance the magnets can approach each other.

It is another object to provide a magnetic window cleaning apparatus with improved tracking characteristics.

These and other objects and advantages of the present invention will become apparent as the same becomes better understood from the following detailed description when taken in conjunction with the accompanying drawings.

DRAWING FIG. 1 is a vertical sectional view through one preferred embodiment of the present invention and illustrating the master and slave units on opposite sides of a window.

FIG. 2 is a partially exploded perspective View of the apparatus shown in FIG. l with the master unit being illustrated in its operating position adjacent one surface of the window, and the slave unit being shown on the other side of the window and generally opposite the master unit, but positioned away from the window for better illustration of its structure;

FIG. 3 is a generally diagrammatic view of the magnetic members of the embodiment of FIGS. l and 2 and illustrating the pattern of the polarity;

FIG. 4 is a sectional view taken generally along line 4 4 of FIG. 2 and on a larger scale to better illustrate the structure of the fastener;

FIG. 5 is a vertical sectional view through another preferred embodiment of the present invention;

FIG. 6 is a generally diagrammatic view of the magnetic members of the embodiment of FIG. 5 and illustrating the pattern of the polarity; and

FIGS. 7 and 8 are small scale views of one magnetic member of each embodiment and indicating the direction of tests on the tracking strength of each pair.

DESCRIPTION Reference is now made more particularly to the drawings wherein similar reference characters indicate the same parts throughout the several views.

The magnetic window cleaning apparatus of FIGS. l-4 includes a master unit, generally designated 10, and a slave unit, generally designated 12. These units are adapted to be positioned on either side of a window 14 opposite one another.

The master unit 10 includes a one-piece magnetic member 20 which is polarized in a plurality of regions as hereinafter more particularly set forth. The'magnetic member 20 is disposed in a housing 22 to which is affixed a handle 24 by means of a reduced neck 26. The handle, neck, and housing are advantageously molded of plastic in one piece as shown. The handle 24 may have a recess to accommodate a plate 27 for advertising or the like.

At the window facing side of the magnetic member 20 is a compressible, resilient layer 32 which is advantageously spongelike and made of polyurethane. The layer 32 is advantageously about $46 to 1/8 inch in thickness and is adhesively secured to the face of the magnetic element 20. In practice, a sheet of window cleaning material, such as paper 34 is placed in position overlying the layer 32 of polyurethane. A fastener, generally designated 36 is then positioned on the outer side of the paper 34 to hold it in position. Preferably, the fastener 36 is spaced from the periphery of the cleaning material 34 to provide an unencumbered peripheral area of the cleaning material for the cleaning operation. The exact structure of the fastener 36 will hereafter be described.

As thus far described, the elements of the master unit 10 find counterparts in the slave unit 12 and the counterparts are indicated by the same numeral followed by the postscript prime Accordingly, a general description of the slave unit is deemed unnecessary. Two differences, however, will be noted. First, there is no handle on the slave unit but rather the housing 22 is provided with an eye 23 through which a chain or string can be passed as a safety measure in utilizing the slave unit. Secondly, it will be noted that the polarity of its magnetic member is generally opposite, as will now be explained.

Referring to FIG. 3, there is diagrammatically illustrated the magnetic members 20 and 20. Preferably, these members are one-piece and are made of barium ferrite material. This material is a ceramic which can be permanently polarized and, as indicated, it is possible to polarize a single large sheet of material in a plurality of regions on its face to provide the preferred structure. In operation, the one-piece construction is generally self-shunting at the side away from the window and no shunting plate is required; however, a shunting plate (not shown) can be used to increase the strength of the magnetic elements by eliminating stray field at the back side. One suitable commercially available material is an oriented ferrite sold under the trademark Indox 5 by Indiana General Corporation. This material may be magnetized in a magnetizing jig suitably arranged to provide the multiple polarity in the alternating patterns shown. As shown, the magnetic members 20 and 20 are polarized in a direction perpendicular to the window with the magnetic element 20 presenting on its window facing side a plurality of pole faces of opposite polarity to those of magnetic member 20. Thus, when disposed in operating position, the magnetic member 20 of master unit and the magnetic member 20 of slave unit 12 are aligned with adjacent pole faces of unlike polarity, as best shown in FIG. l. By this arrangement, the slave unit 12 will follow the master unit 10 as it is moved across the window surface.

Referring now to FIG. 4, there is illustrated the fastener 36' which is identical to the fastener 36. Each fastener is a laminae which includes a layer of ferromagnetic material 41 adjacent the sheet of cleaning material in an outer layer of plastic 42' for engaging the window. In one suitable arrangement, a fastener of generally O-shape is cut out of a sheet of plastic and a layer of iron filings is adhesively secured thereto. It is contemplated, however, that the ferromagnetic material 41' may be a solid layer laminated to the plastic layer 42. In use, the fastener is disposed with the ferromagnetic material 41 adjacent the paper 34 and is attracted by the magnetic element 20. Preferably, however, the fastener overlies only a portion of the cleaning material and magnetic member. ln this manner, the fastener interrupts only a small portion of the ux of the magnetic member so that the opposite magnetic member 20 is still attracted thereby. In utilizing an O-shaped fastener about a quarter of an inch in width, and having the aforementioned iron filings secured thereto, it is possible to interrupt an insignificant portion of the flux of a magnetic member about 3 by 3% inches in size. In this manner, the operation of the master and slave unit is not affected, for all practical purposes.

In selecting the thickness of the fastener 36 or 36', it is preferable that it be not greater than the difference between the compressed thickness and the noncompressed thickness of the layer 32 or 32'. In this manner, the fastener can press into the compressible resilient material 32 or 32 (see FIG. 4) when the apparatus engages the window 14, thus positioning the outer surface of the fastener 36 or 36 generally coplanar with the exposed portion of the cleaning material 34 or 34'. The thickness of the fastener, thickness of the paper, and compressed thickness of the layer 32 or 32 also limits the distance the magnetic elements 20 and 20 can approach each other. Since the strength of the magnetic pull is inversely proportional to the distance between the magnetic members, this arrangement limits the force of attraction. It is necessary to limit the force of attraction in order to limit the amount of friction between the cleaning materials 34 and 34 and the window 14. In addition, the fastener 36 or 36' overlies a portion of the area of the cleaning material and, because it is made of plastic, presents an area having a lesser coeiicient of friction and allows the master and slave units to more easily be moved over the surface of the Window.

The embodiment of FIGS. 5 and 6 has many elements that are identical to those described above; for example, the housing, resilient layer, etc. Accordingly, similar parts are indicated by the same numeral followed by the letter a, and further description is deemed unnecessary. The fastener is also identical and reference is made to the above description thereof.

The major difference in the embodiment of FIGS. 5 and 6 lies in the magnetic members 120 and 120. Again', these members are preferably one-piece and made of a ceramic material which can be permanently polarized. Shunting plates 122, 122 may be conveniently utilized, if desired. The material is magnetized in a magnetizing jig arranged to provide the multiple polarity as shown in FIG. 6. It can :be seen that there are eight poles of equal size on the Window-facing side of each member l and 120. In this manner, the number of north and south poles are equal and this balance makes the magnet more eicient. 1t can also be seen that the pattern at the window-facing side of magnetic member 120 is identical to that at the windowfacing side of member 120'. Production is thereby simpliiied as only one pattern is required and one magnetizing jig can be utilized for both members 120` and 120'.

It can also be seen that magnetic membersV 120 and 120 are arranged with the eight poles in a generally triangular shape. This shape presents lines of opposite polarity along the diagonals of the members and results in improved tracking ability. Referring now to FIGS. 7 and 8, there will be described tests which illustrate this improved result. The tests were performed on a clean, dry, glass window of ls" thickness. The rectangular arrangement (FIG. 7) and the triangular arrangement (FIG. 8) were identical except for the pattern of the polarity. Both sets of magnetic members were formed of oriented ceramic material 3" X 4" X 1/4 in size, with l/s" polyether foam on the window-facing side thereof. The same cleaning paper was used along with the same fasteners 36, 36. Shunting plates, of Ztl-gauge material, were used in both arrangements of these tests.

A master unit and slave unit of each arrangement was placed on the window with a spring gauge attached to the slave unit. The master unit was moved in each direction indicated by arrows x, y, and z, with the spring gauge on the slave unit resisting the movement. These directions represent the width, length and diagonal, respectively, of the magnetic members. Readings were taken on the spring gauge at the maximum tension when the units separated with the following results:

It can be seen that the triangular pattern (8 pole) was superior in all tests. It is believed that the balance of north and south poles aids in this result. Also, Where the corners of several poles meet, there is effectively no magnetism. The rectangular pattern has four such areas, while the triangular pattern has only one such area.

In the diagonal direction z, the triangular pattern is more efficient because there are more direct lines of opposing force. In other words, there are edges of poles lying crosswise of the direction of movement. This is advantageous when the master unit is moved in a circular pattern-the way windows are often cleaned.

It is now deemed apparent that the aforedescribed apparatus provides a new and useful magnetic window cleaning apparatus in which the cleaning material is easily replaced and which utilizes magnetism to hold the cleaning material in position. The combination of elements reduces the friction between the cleaning material and the window and also limits the distance the magnets can approach each other. Additionally, it is deemed apparent that, everything else being equal, the 8-pole, triangular pattern of the pole faces gives improved results.

While preferred embodiments of the present invention have been described, this has been done by way of illustration and not limitation, and it is to be understood that various modifications in structure will occur to a person skilled in the art.

What is claimed is:

I. A magnetic window cleaning apparatus of the type having a window-facing side and permanent magnet means therein, characterized by a layer of cleaning material overlying the window-facing side thereof for engaging and cleaning the window as the apparatus is moved, a fastener made of magnetically-attracted material for attraction by the permanent magnet means to hold the cleaning material in place, and the fastener overlying only a portion of the cleaning material to expose the remainder for its cleaning function.

2. A magnetic window cleaning apparatus as set forth in claim 1 including a layer of compressible, resilient material secured at the window-facing side thereof and between the cleaning material and permanent magnet means.

3. A magnetic window cleaning apparatus as set forth in claim 2 wherein the fastener is a laminae including a layer of ferromagnetic material adjacent the cleaning material and an outer layer of plastic for engaging the window and reducing the friction when the apparatus is moved; the thickness of the laminae being not greater than the difference between the compressed thickness and the noncompressed thickness of the compressible, resilient material; whereby the fastener can compress the compressible, resilient material when the apparatus engages the window to position the outer surface of the fastener generally coplanar with the exposed portion of the cleaning material.

4. A magnetic window cleaning apparatus of the type having a pair of units adapted to be positioned on either side of a window opposite each other, each unit having a window-facing side and permanent magnet means arranged for attracting the opposite unit, one unit being a master unit adapted to be moved over one side of the window and the other unit being a slave unit adapted to follow the master unit, characterized by each unit having a sheet of cleaning material overlying the window-facing side thereof for engaging and cleaning the window as the unit is moved, combination holding and friction reducing means made of magnetically-responsive material attracted by the permanent magnet means for holding the sheet in place and for reducing the friction between the sheet and window so that the units move easily over the window, and the combination holding and friction reducing means arranged to interrupt only a small portion of the flux of the units permanent magnet means so that the opposite unit is attracted thereby.

5. A magnetic window cleaning apparatus as set forth in claim `4 wherein the magnetic means of each unit coimprises a one-piece, multiple-pole magnetic element of generally rectangular shape; each magnetic element being formed of a one-piece ceramic material having, at the window-facing side, only eight triangular pole faces of equal size; the pole faces being arranged so that alternate pole faces have one polarity and the remaining half the opposite polarity; and each unit having the pole faces at the window-facing side arranged in an identical layout to those of the other unit so that, when the units are positioned facing each other, the polarity of each pole face is opposite to the polarity of the pole face of the opposite unit.

6. A magnetic window cleaning apparatus as set forth in claim 4 wherein the combination lholding and friction reducing means comprises a laminae including a layer of ferromagnetic material adjacent the sheet of cleaning material and an outer layer of plastic for engaging the window.

7. A magnetic window cleaning apparatus as set forth in claim 4 wherein the permanent magnet means of each unit is a single piece of magnetic material polarized in a plurality of regions in an identical pattern but each region having a polarity opposite that of the opposite region, and each unit including a layer of compressible, resilient material adhesively secured to the window-facing side of the respective piece of magnetic material which provides a complete backing therefor.

`8. A magnetic window cleaning apparatus as set forth in claim 7 wherein the combination holding and friction reducing means comprises a laminae including a layer of ferromagnetic material adjacent the sheet of cleaning material and an outer layer of plastic for engaging the window and reducing friction when the unit is moved, the laminae thickness being no greater than the difference between the compressed and noncompressed thicknesses of the compressible, resilient material; and whereby the laminae can press into the compressible, resilient material when the unit engages the window to position the outer surface of the laminae generally coplanar with the exposed portion of the sheet of cleaning material.

9. A magnetic window cleaning apparatus as set forth in claim 7 wherein the magnetic material is generally rectangular and made of ceramic, and the plurality of regions are generally triangular in shape and totaling an even number.

10. A magnetic window cleaning apparatus of the type having a pair of units each having a window-facing side and adapted to be positioned on either side of a window opposite each other, one unit being a master unit adapted to be moved over one side of the window and the other unit being a slave unit adapted to follow the master unit, characterized in that each unit has a one-piece, multiplepole magnetic element therein; each magnetic element being made of oriented ferrite material and at the window-facing side thereof being rectangular in shape; each magnetic element having, at ther window-facing side, only eight generally triangular poles faces of generally equal size; the pole faces arranged soi that alternate pole faces have one polarity and the remaining half the opposite polarity; each pole face having an angle at the center of the magnetic element whereby the pole faces are arranged around the center of the one-piece magnetic element and extend therefrom to the periphery of the magnetic element; each unit having the pole faces at the window-facing side arranged in an identical layout to those of the other unit so that, when the units are positioned facing each other, the polarity of each pole face is opposite to the polarity of the pole face of the opposite unit; and a layer of cleaning material overlying the window-facing side of each unit for engaging and cleaning the window as the master unit is moved; whereby both sides of a window are cleaned by movement of the master unit; and means on the window-facing side of each layer of cleaning material for reducing the friction between the cleaning material and the window.

11. A magnetic window cleaning apparatus as set forth in claim 10 wherein the one-piece, multiple-pole magnetic element of each unit is flat, extends to adjacent the periphery of each unit, and provides a backing for the layer of cleaning material across the entire face of the unit.

12. A magnetic window cleaning apparatus of the type having a pair of units each having a window-facing side and adapted to be positioned on either side of a window opposite each other, one unit being a master unit adapted to be moved over one side of the window and the other unit being a slave unit adapted toqfollow the master unit, characterized in that each unit comprises a multiple-pole magnetic element made of oriented ferrite material; each magnetic element being rectangular in shape and having a major longitudinal axis and a minor transverse axis dividing the same into four equal quadrants; the master unit having, at the side opposite the window-facing side, an elongate handle disposed with its longest dimension along said longitudinal axis; each magnetic element having, at the window-facing side, only eight triangular pole faces of equal size and two lying in each quadrant; each magnetic element being polarized in a direction perpendicular to the window and with adjacent pole faces having opposite polarity at the window-facing side; each unit having the pole faces at the window-facing side arranged in an identical layout to those of the other unit so that, When the units are in operative position facing each other, the polarity of each pole face is opposite, respectively, to

the polarity of the pole face of the other unit; each magnetic element being hat over its entire rectangular area and extending to adjacent the periphery of each unit; each unit having a sheet of cleaning material overlying the window-facing thereof for engaging and cleaning the window as the unit is moved; said tlat magnetic element providing backing support for the sheet of cleaning material; and means on the window-facing side of each sheet of cleaning material for reducing the friction between the sheet and the window.

13. A magnetic window cleaning apparatus of the type having a pair of units each having a window-facing side and adapted to be positioned on either side of a window opposite each other, one unit being a master unit adapted to be moved over one side of the Window and the other unit being a slave unit adapted to follow the master unit, characterized in that each unit has a one-piece, multiplepole magnetic element therein; each magnetic ele-ment being made of oriented ferrite material and at the window-facing side thereof being at, generally rectangular in shape, and extending adjacent the periphery of each unit; each unit having pole faces at the window-facing side arranged so that, when the units are positioned opposite each other, the polarity of each pole face is opposite to the polarity of the pole face of the opposite unit; a layer of cleaning material overlying the Window-facing side of each unit 4for engaging and cleaning the window as the master unit is moved, whereby both sides of a window are cleaned by movement of the master unit; means of plastic material on the window-facing side of each layer of cleaning material for reducing the friction between the cleaning material and the window; and the magnetic element of each element providing the backing for the layer of cleaning material across the entire face of the unit.

References Cited UNITED STATES PATENTS 3,208,090 9/1965 Roesel, Ir. 15-220.1 3,296,645 1/1967 Shore l5-220.1

FOREIGN PATENTS 888,344 l/1962 Great Britain 15-220.1

LEON G. MACHLIN, Primary Examiner 

